Revenue (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue	$ 506,871,000	$ 491,355,000	$ 1,512,413,000	$ 1,366,721,000
Renewable service term period			1 year
Description of timing			The significant majority of the Company’s contracts with customers have an initial term of one year or less
Renewal term			1 year
Minimum agreement period for account of unsatisfied performance obligations			1 year
Housekeeping
Disaggregation of Revenue [Line Items]
Percent of revenue			48.50%	53.70%
Revenue	242,208,000	247,395,000	$ 734,164,000	$ 733,737,000
Dietary
Disaggregation of Revenue [Line Items]
Percent of revenue			51.50%	46.30%
Revenue	264,663,000	$ 243,960,000	$ 778,249,000	$ 632,984,000
Minimum
Disaggregation of Revenue [Line Items]
Cancellation notice period			30 days
Initial period preceding cancellation notice			60 days
Maximum
Disaggregation of Revenue [Line Items]
Cancellation notice period			90 days
Initial period preceding cancellation notice			120 days
Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Contract liabilities	0		$ 0		$ 0
Transferred over Time
Disaggregation of Revenue [Line Items]
Contract liabilities	$ 0		$ 0		$ 0